Laser-driven hydrothermal processing

ABSTRACT

Systems for processing a material by submerging the material in a fluid and directing laser pulses at the fluid and the material for processing the material. An embodiment removes the surface of concrete, brick, or rock or minerals in a relatively gentle, energy-efficient, and controlled manner that also confines the material that is removed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit under 35 U.S.C. §119(e) of U.S.Provisional Patent Application No. 61/752,823 filed Jan. 15, 2013entitled “method and apparatus for laser processing of solids,” thedisclosure of which is hereby incorporated by reference in its entiretyfor all purposes.

This application claims benefit under 35 U.S.C. §119(e) of U.S.Provisional Patent Application No. 61/752,901 filed Jan. 15, 2013entitled “efficient laser-enhanced dissolution of minerals and debrisvia acid chemistry and hydrothermal conditions,” the disclosure of whichis hereby incorporated by reference in its entirety for all purposes.

This application claims benefit under 35 U.S.C. §119(e) of U.S.Provisional Patent Application No. 61/754,142 filed Jan. 18, 2013entitled “periodic application of laser-driven sample processing,” thedisclosure of which is hereby incorporated by reference in its entiretyfor all purposes.

STATEMENT AS TO RIGHTS TO APPLICATIONS MADE UNDER FEDERALLY SPONSOREDRESEARCH AND DEVELOPMENT

The United States Government has rights in this application pursuant toContract No. DE-AC52-07NA27344 between the United States Department ofEnergy and Lawrence Livermore National Security, LLC for the operationof Lawrence Livermore National Laboratory.

BACKGROUND

1. Field of Endeavor

The present application relates to processing and more particularly toLaser-Driven Hydrothermal Processing.

2. State of Technology

Removal of the surface of materials such as concrete, brick, androck/minerals can be accomplished via grinding or intense abrasive waterjets or electric-discharge shock chipping and flaking of concrete. Laserscabbling, which uses a 5 kW laser to heat concrete in air to itsboiling/flaking/cracking point has been demonstrated. None of theseprocesses employs transient dissolution of the surface as its primarymechanism and none offers gentle, μm-scale control of the materialremoval.

“Laser peening” uses intense laser pulses also directed at metal targetsthat are submerged in water, in order to generate a plasma andcounter-propagating shock waves at the interface between the metaltarget and the water. The interaction between laser pulses and a metaltarget, whether submerged or not, is fundamentally different than theinteraction between laser pulses and a dielectric target, such asconcrete, brick, or rocks. Conductors, such as metals, possess vastlyhigher electrical conductivity than do dielectrics, and the laser lightstriking a metal target is absorbed entirely within a skin depth that isat most a few μm. Except in cases of extremely high-power laser pulses,whose use would be inappropriate for an energy-efficient, gentle, andcontrolled process, dielectric materials absorb light over a much longerpenetration depth. Because metals absorb the laser pulses so strongly,it is not surprising that it is relatively easy to generate hightemperatures and pressures at the interface between a submerged metaland the submerging fluid.

Hydrothermal processing is a technique to grow purified crystals ofmaterials including quartz [SiO₂] and emerald [Be₃(Al,Cr)₂Si₆O₁₈].Information about hydrothermal processing is provided in the article:“Pulsation processes at hydrothermal crystal growth (beryl as example),”Journal of Crystal Growth 206, 203-214 (1999) by V. G. Thomas, S. P.Demin, D. A. Foursenko, and T. B. Bekker and the article “Hydrothermalgrowth of α-quartz using high-purity α-cristobalite as feed material,”Materials Research Bulletin 28, 1201-1208 (1993) by M. Hosaka and T.Miyata. Average growth temperature for beryl was −600° C. and pressurewas 1.5 kbar for pure water at given temperatures. The duration of runswas 15 to 25 days, growth rate was 0.1 mm/day. For quartz, the growthwas carried out for 5-22 days. Quartz growth rates, in growth with highdegree fillings exceeding 75%, were approximately 0.2-0.6 mm/day in theZ direction and approximately 0.1-0.2 mm/day in the X direction.Traditional hydrothermal processing requires containment vessels thatcan withstand sustained high temperatures and pressures and the processis very slow. Thus, traditional hydrothermal processes would have nopractical application to treating large surfaces of buildings, etc.

SUMMARY

Features and advantages of the disclosed apparatus, systems, and methodswill become apparent from the following description. Applicants areproviding this description, which includes drawings and examples ofspecific embodiments, to give a broad representation of the apparatus,systems, and methods. Various changes and modifications within thespirit and scope of the application will become apparent to thoseskilled in the art from this description and by practice of theapparatus, systems, and methods. The scope of the apparatus, systems,and methods is not intended to be limited to the particular formsdisclosed and the application covers all modifications, equivalents, andalternatives falling within the spirit and scope of the apparatus,systems, and methods as defined by the claims.

This application covers apparatus, systems, and methods for processing amaterial by submerging the material in a fluid and directing laserpulses at the fluid and the material for processing the material.

It is an object to provide an improved means and method for removingmatter from the surface of solid materials.

A further object is to provide a pulsed-laser-based method to remove thesurface of concrete, brick, or rock or minerals in a relatively gentle,energy-efficient, and controlled manner that also confines the materialthat is removed.

A further object is to provide a pulsed-laser-based method to remove thesurface of concrete, brick, or rock or minerals that can be submerged ina fluid or covered with a flowing fluid that can perform hydrothermalprocessing, at least in a transient manner, in a relatively gentle,energy-efficient, and controlled process that also confines the materialthat is removed.

A further object is to provide a pulsed-laser-based method to removecontamination from the surface of concrete, brick, or rock or minerals,included painted surfaces, including lead-based paints or surfacescontaminated with other heavy metal compounds that can be submerged in afluid or covered with a flowing fluid in a relatively gentle,energy-efficient, and controlled process that also confines the materialthat is removed.

A further object is to provide a pulsed-laser-based method both toremove contamination from the surface of concrete, brick, or rock orminerals and to monitor the concentration of the contamination,real-time, while the decontamination is proceeding.

A further object is to provide a pulsed-laser-based method to performdecontamination of surfaces from beryllium and/or its oxides and otherberyllium compounds or actinides and/or their oxides and other actinidecompounds, using water as either a stagnant or flowing medium on thesurface being decontaminated.

A further object is to provide a method for analyzing the concentrationsof rare-earths in ores.

A further object is to provide a pulsed-laser-based analytical method tomeasure the concentration profile of various elements versus depth inconcrete, brick, or rock or minerals.

A further object is to provide a rapid, relatively energy-efficientmethod to recrystallize materials that are amenable to hydrothermalprocessing.

Other objects and advantages will become apparent from the followingdescription and accompanying drawings.

Additional information about Applicant's apparatus, systems, and methodsare provided in the article: “Laser comminution of submerged samples,”Journal of Applied Physics 114(2013) by R. Mariella, A. Rubenchik, M.Norton, and G. Donohue. The article, “Laser comminution of submergedsamples,” Journal of Applied Physics 114(2013) by R. Mariella, A.Rubenchik, M. Norton, and G. Donohue is incorported heriein by thisreference for all purposes.

The apparatus, systems, and methods are susceptible to modifications andalternative forms. Specific embodiments are shown by way of example. Itis to be understood that the apparatus, systems, and methods are notlimited to the particular forms disclosed. The apparatus, systems, andmethods cover all modifications, equivalents, and alternatives fallingwithin the spirit and scope of the application as defined by the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated into and constitute apart of the specification, illustrate specific embodiments of theapparatus, systems, and methods and, together with the generaldescription given above, and the detailed description of the specificembodiments, serve to explain the principles of the apparatus, systems,and methods.

FIG. 1A illustrates the initial absorption and heating of the surface ofthe solid material.

FIG. 1B illustrates the expansion of the transiently-heated andpressurized layer of water.

FIG. 1C illustrates the post-process rock and nearby water.

FIG. 2 illustrates an apparatus, system, and method for profiling.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Referring to the drawings, to the following detailed description, and toincorporated materials, detailed information about the apparatus,systems, and methods is provided including the description of specificembodiments. The detailed description serves to explain the principlesof the apparatus, systems, and methods. The apparatus, systems, andmethods are susceptible to modifications and alternative forms. Theapplication is not limited to the particular forms disclosed. Theapplication covers all modifications, equivalents, and alternativesfalling within the spirit and scope of the apparatus, systems, andmethods as defined by the claims.

This application deals with the removal or alteration of material.Disclosed are apparatus and systems to implement a method that usespulses of light energy to remove and/or alter a solid that is submergedin a fluid. The submerging fluid, which may be nominally stagnant orintentionally flowing/convected, needs to transmit the pulses of lightenergy and the solid needs to absorb these pulses of light energy at itssurface. One apparatus and system is to use pulses of ultraviolet lightfrom a laser as the source of pulsed light energy and to use water asthe submerging fluid. There are at least three regimes of operation thatare accessible with the new apparatus, systems, and methods:

Regime 1—Lower-power regime: purification/recrystallization of surfacematerial via transient dissolution,

Regime 2—Modest-power regime: removal of surface material via transientdissolution, and

Regime 3—Higher-power regime: removal of surface material via transientdissolution and disruption of coherent/adherent forces within the solid.

Regimes 1 and 2 offer a controlled, relatively gentle, and well-confinedmethod to remove and/or alter the surface of a solid. The target, then,may be concrete, brick, or a variety of rocks or minerals, as examples.If non-volatile toxic and/or radioactive contamination of the surface ispresent, then this laser-driven hydrothermal processing [“LDHP”] offersa new method and means to decontaminate the surface, while containingthe removed hazardous material, especially with no release of hazardousaerosols in the process.

For silicate materials that are submerged in water, apurification/recrystallization of silica [SiO₂] is normally observedwith LDHP.

When the target is concrete that is submerged, the LDHP can be adjustedeffectively to un-cement the material that is adhering/bound to thesurface, along with the surface of the concrete, itself. This includesremoving paint and contamination of the concrete surface, includingcontamination that may be on the solid surface, within or underneath thepaint.

Although one aspect of this application is the removal of material, thegrowth of purified crystals is another aspect that could be applied tothe production of seed crystals or purification of surfaces of existingcrystals, if their growth can be effected via a hydrothermal process.

One application of the gentle, controlled removal of material that LDHPoffers is the profiling of contamination versus depth for analyticalpurposes, including the verification of decontamination that may havebeen performed, already.

Basically, this application is based upon the discovery of a new regimein Chemistry and Physics, namely a transient hydrothermal state, thatcan be accessed by passing modest-power laser pulses through atransparent submerging fluid and directing these pulses onto the surfaceof polycrystalline dielectric material such as concrete, brick, or rock,including painted versions of these. This new regime cannot be accessed,when the submerged target material is transparent to the laser light,such as is the case with visible or most ultraviolet light [“UV” light]and when the target is “UV-grade fused silica” for example. Because ofthis, one can use the apparatus, systems, and methods with a sample suchas concrete, brick, rock, including painted samples, by passing thelaser pulses through a UV-grade fused silica window as well as water orother transparent fluid in order to make the pulses strike the desiredsurface, as reported. The pulse duration and energy density [“fluence”]can fall within a fairly wide range and still produce theenergy-efficient, gentle, and controlled, confined removal and/orrecrystallization of the target material, but there needs to besufficient energy deposited into the surface of the target material toheat both the target and the adjacent fluid, such as water, rapidly tohigher temperature and temperature, at which point the fluid exhibitsgreatly-increased dissolving power of most or all of the targetmaterial. This process is based on several principles:

-   -   Transparency of the fluid to the laser pulses,    -   Absorbance of the laser pulses on the surface of the submerged        solid target material,    -   Duration of the laser pulse being less than the rate of thermal        conduction of the absorbed laser-pulse energy for the dimensions        of the laser-pulse absorption,    -   If the increased dissolving power of the fluid depends upon        increased pressure, then the duration of the laser pulse must be        less than the time for the higher fluid pressure at the solid's        surface to dissipate, and    -   Increased dissolving power of the fluid, due to the local        heating of the solid surface and rapid conduction of this heat        into the adjacent fluid.

Laser-Driven Hydrothermal Processing [“LDHP”].

As used in this application, the word “hydrothermal,” means acircumstance in which a fluid is driven into a condition of temperatureabove room temperature and pressure above atmospheric pressure, in whichcondition the fluid exhibits greatly increased dissolving power ofmaterials of interest. For example, with water, driving it into itssupercritical state requires temperatures>374° C. and pressures>218 atm,and supercritical water dissolves quartz and other oxides to a muchgreater extent that does water at room temperature and atmosphericpressure.

As used in this application, the word “contaminants,” means minorityelements or minority compounds found in the main material.

Examples of the practice of Applicants methods and systems utilizes:

#1—a laser able to deliver onto the target material pulses of light withsufficient intensity [power per unit area] and fluence [energy per unitarea] to produce rapid heating of a submerged target material;

#2—a chamber or other method to contain the target material that issuspended in or covered with the fluid, such as liquid water, with atleast one window, such as fused silica, that is transparent to the laserpulses or a method to produce a sheath or covering flow of fluid overthe surface of the target material, such as water that is used incommercial laser peening;

#3—a fluid that is transparent to the laser light and that, at higherpressures and temperatures, exhibits greatly increased dissolving powerof the materials of interest;

#4—a target material that is compatible with the submerging fluid andthat absorbs the laser light strongly enough to become heated and,concomitantly, transiently heats and pressurizes the adjacent fluid sothat it has increased dissolving power.

EXAMPLES

Applicants constructed and tested various examples of apparatus,systems, and methods: two lasers and three wavelengths of light havebeen used, successfully, as well as a range of fluences and lightintensities, with concrete, brick, and quartzite targets. [Quartzite isa metamorphic rock, formed from what was originally sandstone.]

One laser was a custom-built laser based on a Nd:glass zig-zag slabamplifier, with fundamental output at 1053 nm, capable, with a frequencydoubler, of emitting 527-nm light or, with a frequency tripler, 351-nmlight, whose output is roughly rectangular, 15 mm×17 mm, with anominally flat intensity profile and pulse duration adjustable between 8and 20 ns. For some of the experiments, a UV-transmitting lens was usedto decrease the spot size on the target surface.

A second laser was a commercial Excimer laser [Coherent-Lambda PhysikLPX300 laser], generating 25-ns light pulses at 248-nm wavelength in a12×30 mm spot. This latter laser was used with a UV-transmitting lens todecrease the spot size on the target surface.

The LDHP example experiments that are described in this application usedstainless-steel chambers, open to the air and partially filled withdeionized water, with UV-grade fused-silica windows to admit the laserpulses into the system. Although the Applicants have not attempted toenclose the chamber in which the LDHP has been studied, there is nofundamental reason that a sealed chamber, capable of operating at anintermediate temperature and pressure could not be used, nor is thereany fundamental reason that a sealed chamber could not be used with atube or other gaseous-flow device installed above the water or otherfluid that could sample any gases that were released from the targetsurface by the LDHP laser pulses. This could include the intentional useof a flow of sampling gas, such as nitrogen or argon, to sweep away anyreleased gases to a monitor, such as a mass spectrometer or ion-mobilityspectrometer. This could be valuable, for example, if there were anyradioactive materials within the solid target that had decayed intoradon or other rare gas that had, subsequently, been trapped within thesolid.

The LDHP example experiments that are described in this application usedwater as the submerging fluid; for transmission distances of a few cm orless, water is transparent to light with wavelengths from 1000 nmthrough 200 nm.

The effective absorption of the quartzite, concrete, brick was highenough to attain the conditions for hydrothermal processing of thematerial. Both the 527-nm and 351-nm laser wavelengths have demonstratedthe LDHP, with the former primarily producing recrystallization ofsilica on the surface of quartzite at fluences of roughly 0.8 J/cm² andthe 351-nm laser pulses primarily removing material from quartzite atfluences of 7 J/cm² and 3.5 J/cm². With concrete, the 351-nm laser at0.4 J/cm² on concrete preferentially removed the cement. The 248-nmExcimer laser, with 0.6 J focused to a roughly 2 mm×5 mm spot primarilyremoved material from commercial quartzite flooring and removed cement,preferentially, from concrete aggregate.

Laser-Enhanced Dissolution and Recrystallization

Examination of the post-LDHP quartzite sample revealed one surprisingphenomenon—surrounding the material-removal zone were relatively large,colorless crystals, which we later identified as relatively pure Si0₂.The colorless crystals that appeared on the quartzite were theindication that some modification of material was taking place at laserfluences even below the traditional ablation threshold. In our nextexperiment, we used an unfocused laser with 2.5-cm² area, directed ontoa broken piece of concrete, and measured removal material that proceededwithout having produced a visible crater. The resulting distribution ofsub-pm-scale particles was virtually identical to that which we observedfrom a focused laser on quartzite [rock]. Weighing the sampledemonstrated the weight reduction with removal rate 4.5*10⁴ g/J orremoval energy 2.2 kJ/g, which is much less than the evaporation energyfor silica −10 kJ/g., hence our mechanism is more efficient than thedirect evaporation. We explain the result by the fact that thetransient, near-surface, hot, high-pressure water has greatly-enhanceddissolving power and effectively dissolved the heated solid surface,including the Si02 component of quartzite, even though Si02 is notsoluble in water under atmospheric-pressure conditions.

Referring now to the drawings and in particular to FIGS. 1A, 1B, and 1C;a schematic representation for the process is provided, usingultraviolet laser pulses, a silicate rock as the absorbing solid, andwater as the submerging fluid. FIG. 1 A is an illustration of theinitial absorption and heating of the surface of the solid material,which concomitantly heats the water and transiently dissolves most orall of a surface layer. FIG. 1B is an illustration of the expansion ofthe transiently-heated and pressurized layer of water, generatingnanocrystals from the supersaturated solution that forms, as the layercools and expands. FIG. 1C is an illustration of the post-process rockand nearby water, showing the possible suspension of the nanocrystalsthat formed as well as SiO₂ that recrystallized on the solid surface.The physical orientation of the solid target material is not pertinent,so long as the laser pulse illuminates the surface of interest and thatsurface is able to absorb the laser-pulse energy.

A test apparatus 100 is shown in FIGS. 1A, 1B, and 1C. The testapparatus 100 includes a vessel 102, a laser 104, a laser beam 106, awater bath 108, a superheated layer 110, and a solid 112. FIG. 1Aillustrates the initial absorption and heating of the surface of thesolid material 112, which concomitantly heats the water 108 andtransiently dissolves most or all of a surface layer 110.

FIG. 1B illustrates the expansion of the transiently-heated andpressurized layer of water 114, generating nanocrystals 116 from thesupersaturated solution that forms, as the layer cools and expands.

FIG. 1C illustrates the post-process rock and nearby water, showing thepossible suspension of the nanocrystals 118 that formed as well as SiO₂that recrystallized on the solid surface. The physical orientation ofthe solid target material is not pertinent, so long as the laser pulseilluminates the surface of interest and that surface is able to absorbthe laser-pulse energy.

Applicants determined that the following sequence of events occurs: theabsorption of the laser pulse on the surface of the solid target heatsthe surface and collaterally generates a transient thin layer ofhigh-pressure and high-temperature water, held by inertia, probably fortime scales only of ns or μs, in contact with the concrete or othersurface. During this time, a hydrothermally-enhanced dissolution of theoxides and other components proceeds. As the thin layer expands andcools, the transiently-dissolved substrate precipitates out, forming toa large extent sub-μm-scale particles and, when in direct contact withthe solid surface, some adherent crystals.

Applicants determined that if a second laser pulse were to strike thesurface at the same time as when, or slightly before, the collapsingbubble struck the surface, then the local pressure and temperature, andhence, the dissolution, would be enhanced. Since it is likely that anyapplication of laser comminution of concrete or other surfaces would bedone with a pulse train, anyway, it would fit in rather well to tune thetime separation of pulses to match the natural relaxation frequency ofthe formation and collapse of the bubble. Applicants estimate for theirstudies that used 0.4 J/cm² of 15-ns, 351-nm light that the relaxationtime was 140 μs, based on published data from Alloncle, et al., shownbelow. That is, there may be a particularly efficient repetition ratefor comminution of the surface, based on the natural relation time ofbubbles that are formed on the surface.

Applicants observed narrow particle-size distributions of the particlesthat were launched into the submerging water. The particle-sizedistributions from the different samples were similar to one another,and dissimilar to the grain and particle sizes in the solid targets:

Although, in principle, Applicants' apparatus, systems, and methods canbe practiced with lower total energy per pulse and a smaller laser spotor with a Gaussian or other peaked intensity profile, the preferredembodiment is to use a higher-pulse-energy, flat-topped intensityprofile, such as is produced by the SLAB laser, or quasi-flat-toppedintensity profile, such as is commonly produced by commercial excimerlasers. If a laser with a peaked profile must be used, the preferredembodiment would be to incorporate a beam homogenizer, possibly withimaging optics to adjust the spot size to a desired surface area, toperform the processing. The reason for these considerations is thatthere is a minimum threshold of intensity-and-fluence in LDHP, so that alarger beam with a flat-topped intensity profile will utilize a largerfraction of the total beam spot on the target material for the LDHP, andwill perform the process more uniformly than will a laser spot with apeaked intensity profile. The minimum threshold is material-dependent,with the lowest threshold that Applicants observed being that for thecement in concrete, at approximately 0.4 J/cm² in a UV-laser pulsebetween 8 and 25 ns, and the highest being that for light-colored sandor quartz, at approximately 1.5 to 2 J/cm² for similar-duration UV laserpulses.

Although it there are lasers that emit picosecond or femtosecond laserpulses, they would not be in our preferred embodiment, for one primaryreason: no matter what the pulse duration, for any given wavelength oflight, the solid target material needs to absorb sufficient light energyin order for the laser pulse to heat it, directly. Shorter laser pulses,therefore, must have higher intensities [fluence=Intensity*pulseduration] to deliver the same amount of energy to heat the targetmaterial and the adjacent fluid. Higher intensities carry with them theincreased probability for causing dielectric breakdown and plasma at theinterface between the solid target and its submerging fluid. Generatingdielectric breakdown and plasma are undesirable for the LDHP, becausethe LDHP needs intimate contact between the submerging fluid and thesolid target being heated with the laser pulse.

Concrete, which normally contains Portland cement [heated CaCO₃], sand,and possibly larger pebbles, is an example of an impure material that iseffectively un-cemented with this process. Evidence that the processincorporates a transient dissolution step is that the observed particlesizes do not depend upon the grains or particle sizes in the startingmaterial [for cement, for example, the size distribution itself isextremely broad, typically spanning two or three decades from thesubmicrometer range to 100 μm], but resemble each other for a range ofsolid targets. The sub-μm nature of the distribution of particle sizesis also consistent with a rapid transition from dissolved layer throughsupersaturated layer through nucleation and growth of particles, forminga suspension or colloid.

Modest intensities and fluences can be and need to be used to produce anenergy-efficient and confined process, because the process does notproceed via formation of a plasma—there is no dielectric breakdown.Indeed, as mentioned above, dielectric breakdown and plasma formationare undesirable, because intimate contact between the solid target andthe submerging fluid is required for direct dissolution and formation ofa plasma would disrupt the intimate contact. Also, the target materialneed not be heated to sublimation or boiling temperatures, whichaccounts for the much-improved energy efficiency of this process and itsrelatively gentle and confined nature.

A pressure vessel is not needed, since the fluid that surrounds thelayer that is adjacent to the illuminated surface serves to confine thebuildup of pressure and temperature in the layer of fluid that isadjacent to the surface. The mechanism for rapid removal of the cementin concrete [which is a mixture of CaCO₃ and CaO is unknown at thistime, but there is evidence that high pressure, high-T water dissolvescalcite, which is a form of CaCO₃.

Referring now to FIG. 2, an apparatus, system, and method for profilingis illustrated. The apparatus, system, and method are designatedgenerally by the reference numeral 200. The apparatus, system, andmethod uses water 204 directed to the surface 202 being profiled. Thewater 204 forms a water sheath 208. A laser source 210 produces a laserbeam 212. The laser beam 212 is directed to the water sheath 208 and thesurface 202 being profiled. The water 204 moves in flow direction 214 toa waste collector 216. This provides flow for the fluid collection andarchiving system 220. An optional flow 218 to ICP-MS for real-timeanalytical monitoring of contamination or other compositional analysisis shown.

The LDHP that is described, here, is a pulsed process. As such, eachpulse energy and fluence can be tuned to remove material, gently, and ina contained manner. If the physical arrangement is one of a flowingsheath, the passing fluid, such as water, collects all non-gaseousmaterials that were removed during that pulse and transports them awayfrom the spot where the laser stuck the surface. By collecting theliquid flow from each pulse, for example by sucking the fluid into atube and passing that flow through a multi-receptacle receiver, thematerial removed by each pulse can be archived for later analysis in itsown aliquot of fluid. Either with pre-knowledge of the overall processon the material of interest or by measurements made during the LDHP ofthe location of interest, the operator can, knowing the spot area andthe depth of material removed, quantitatively convert concentrations ofmaterials of interest in each aliquot to surface concentrations versusdepth, thus profiling the concentrations of materials of interest. Inthis manner, one can measure the profile of concentration of acontaminant versus depth.

EXAMPLE

Profile of beryllium and its compounds versus depth in quartzite orsimilar flooring or building material [density=2.65 g/cm³], with energycost Q*=4 kJ/g [which equates to 10.6 kJ/cm³], using water a flowingsheath over the quartzite surface and UV laser pulses at 248-nmwavelength.

Using a pulsed UV laser with spot size of 0.1 cm² and pulse energy of0.2 J, then each laser pulse would remove a 0.00019-cm-thick layer ofthe quartzite, which can be expressed as 1.9 μm of depth removed perlaser pulse. Thus, in principle, the concentration of beryllium as acontaminant can be measured with roughly 2-μm precision. Practicalconsiderations, such as rate of water flow and sensitivity of theanalytical technique for the various chemical forms of beryllium willlimit the overall sensitivity of this profiling measurement.

In Applicant's discussions with cognizant individuals regarding thedecontamination of beryllium-contaminated surfaces, it has been statedthat the primary health risk associated with such surfaces is the [re-]aerosolization of the beryllium and/or its compounds, which can lead toinhalation and possible acute chemical pneumonitis or berylliosis.

The apparatus, systems, and methods described above of a transienthydrothermal process that transiently dissolves submerged rock,concrete, or brick, and, hence, intrinsically contains any contaminationthat is removed along with the surface, the presence of large equipmentmoving around a building as is it performing the decontamination couldpotentially disturb and aerosolize the beryllium contamination that isnot submerged under a sheath of water. The apparatus, systems, andmethods include preparing the surfaces, prior to laser treatment, in amanner that both prevents accidental Aerosolization of the berylliumcontaminant and yet does not significantly impede the laser processing.In fact, it can serve as a visual indicator of progress in surfacetreatment—paint the surface! Normal paints consist of titanium dioxidewith latex or other organic binder. These materials will be removed,readily, by the pulsed-UV-laser-driven hydrothermal process, exposingthe underlying concrete, stone, or brick—while still submerged under asheath of water and, thus, still confining and containing the berylliumcontaminant. The net effect is to make the overall decontaminationprocess environmentally safer, with reduced health risk.

While one is performing the profiling technique, described immediatelyabove, one could attach a small tube with accurately-measured flow rate[such as 60 microliters/s] between the main flow and an ICP-MS, such asan Agilent 7500, with input nebulizer [and solvent stripper, if needed]so that the analytical instrument can provide immediate feedback aboutlevels of contamination by Be and its compounds and similarcontaminants, while simultaneously providing the capability to archivethe majority of the removed material, in aliquots, if desired, traceableto the physical location of the point of their removal.

By measuring the ratio of the flow rate to the ICP-MS system to that ofthe main flow, one can convert the concentration of beryllium measuredwith the ICP-MS to the concentration of beryllium on the surface beingprofiled. This could be of considerable value if the LDHP profilinganalytical procedure were being used as a confirmation for lack ofpresence of beryllium on a surface.

To accelerate the process Applicants suggest to use as a submergingliquid an acid or base or salt most suitable for a particular targetmaterial, thus increasing the dissolution rate, so long as the presenceof these added chemicals to the fluid do not interfere with thetransmission of the laser pulses to the surface of the target material.For example, all nitrates and acetates are soluble, so using dilutenitric or acetic acid may retain all metals in solution. Empiricalstudies are required to optimize this process.

Although the description above contains many details and specifics,these should not be construed as limiting the scope of the applicationbut as merely providing illustrations of some of the presently preferredembodiments of the apparatus, systems, and methods. Otherimplementations, enhancements and variations can be made based on whatis described and illustrated in this patent document. The features ofthe embodiments described herein may be combined in all possiblecombinations of methods, apparatus, modules, systems, and computerprogram products. Certain features that are described in this patentdocument in the context of separate embodiments can also be implementedin combination in a single embodiment. Conversely, various features thatare described in the context of a single embodiment can also beimplemented in multiple embodiments separately or in any suitablesubcombination. Moreover, although features may be described above asacting in certain combinations and even initially claimed as such, oneor more features from a claimed combination can in some cases be excisedfrom the combination, and the claimed combination may be directed to asubcombination or variation of a subcombination. Similarly, whileoperations are depicted in the drawings in a particular order, thisshould not be understood as requiring that such operations be performedin the particular order shown or in sequential order, or that allillustrated operations be performed, to achieve desirable results.Moreover, the separation of various system components in the embodimentsdescribed above should not be understood as requiring such separation inall embodiments.

Therefore, it will be appreciated that the scope of the presentapplication fully encompasses other embodiments which may become obviousto those skilled in the art. In the claims, reference to an element inthe singular is not intended to mean “one and only one” unlessexplicitly so stated, but rather “one or more.” All structural andfunctional equivalents to the elements of the above-described preferredembodiment that are known to those of ordinary skill in the art areexpressly incorporated herein by reference and are intended to beencompassed by the present claims. Moreover, it is not necessary for adevice to address each and every problem sought to be solved by thepresent apparatus, systems, and methods, for it to be encompassed by thepresent claims. Furthermore, no element or component in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element or component is explicitly recited in the claims. Noclaim element herein is to be construed under the provisions of 35U.S.C. 112, sixth paragraph, unless the element is expressly recitedusing the phrase “means for.”

While the apparatus, systems, and methods may be susceptible to variousmodifications and alternative forms, specific embodiments have beenshown by way of example in the drawings and have been described indetail herein. However, it should be understood that the application isnot intended to be limited to the particular forms disclosed. Rather,the application is to cover all modifications, equivalents, andalternatives falling within the spirit and scope of the application asdefined by the following appended claims.

1. A method of processing a material, wherein the material has asurface; comprising the steps of: covering the material with a liquidproviding an interface between the surface of the material and saidliquid, directing pulses of light onto the surface of the material suchthat the interaction of said light pulses with the surface of thematerial generates local pressure and temperature producing a transienthydrothermal layer at the interface between said liquid and the surfaceof the material, wherein said transient hydrothermal layer at leastpartially dissolves the material.
 2. The method of processing amaterial, wherein the material has a surface, of claim 1 wherein saidstep of directing pulses of light onto the surface of the materialcomprises using a laser for directing pulses of light onto the surfaceof the material.
 3. The method of processing a material, wherein thematerial has a surface, of claim 1 wherein said step of directing pulsesof light onto the surface of the material comprises using a laser withvisible or ultraviolet wavelengths for directing pulses of light ontothe surface of the material.
 4. The method of processing a material,wherein the material has a surface, of claim 1 wherein said step ofdirecting pulses of light onto the surface of the material comprisesusing an array of lasers with visible or ultraviolet wavelengths fordirecting pulses of light onto the surface of the material.
 5. Themethod of processing a material, wherein the material has a surface, ofclaim 1 wherein said step of directing pulses of light onto the surfaceof the material comprises directing pulses of light onto the surface ofthe material such that the interaction of said light pulses with thesurface of the material generates local pressure and temperatureproducing a transient hydrothermal layer at the interface between saidliquid and the surface of the material, wherein said transienthydrothermal layer at least partially dissolves the material producingparticles that are suspended in said liquid.
 6. The method of processinga material, wherein the material has a surface, of claim 1 whereincontaminants are associated with the material and wherein said step ofdirecting pulses of light onto the surface of the material comprisesdirecting pulses of light onto the surface of the material such that theinteraction of said light pulses with the surface of the materialgenerates local pressure and temperature producing a transienthydrothermal layer at the interface between said liquid and the surfaceof the material, wherein said transient hydrothermal layer at leastpartially dissolves the material producing particles that are suspendedin said liquid and at least partially dissolves or removes thecontaminants.
 7. The method of processing a material, wherein thematerial has a surface, of claim 1 wherein beryllium contaminants areassociated with the material and wherein said step of directing pulsesof light onto the surface of the material comprises directing pulses oflight onto the surface of the material such that the interaction of saidlight pulses with the surface of the material generates local pressureand temperature producing a transient hydrothermal layer at theinterface between said liquid and the surface of the material, whereinsaid transient hydrothermal layer at least partially dissolves thematerial producing particles that are suspended in said liquid and atleast partially dissolves or removes the beryllium contaminants.
 8. Themethod of processing a material, wherein the material has a surface, ofclaim 1 wherein radioactive contaminants are associated with thematerial and wherein said step of directing pulses of light onto thesurface of the material comprises directing pulses of light onto thesurface of the material such that the interaction of said light pulseswith the surface of the material generates local pressure andtemperature producing a transient hydrothermal layer at the interfacebetween said liquid and the surface of the material, wherein saidtransient hydrothermal layer at least partially dissolves the materialproducing particles that are suspended in said liquid and at leastpartially dissolves or removes the radioactive contaminants.
 9. Themethod of processing a material, wherein the material has a surface, ofclaim 1 wherein rare earths contaminants are associated with thematerial and wherein said step of directing pulses of light onto thesurface of the material comprises directing pulses of light onto thesurface of the material such that the interaction of said light pulseswith the surface of the material generates local pressure andtemperature producing a transient hydrothermal layer at the interfacebetween said liquid and the surface of the material, wherein saidtransient hydrothermal layer at least partially dissolves the materialproducing particles that are suspended in said liquid and at leastpartially dissolves or removes the rare earths contaminants.
 10. Themethod of processing a material, wherein the material has a surface, ofclaim 1 wherein said step of covering the material with a liquidcomprises covering the material with an acidic liquid.
 11. The method ofprocessing a material, wherein the material has a surface, of claim 1wherein said step of covering the material with a liquid comprisescovering the material with an alkaline liquid.
 12. The method ofprocessing a material, wherein the material has a surface, of claim 1wherein said step of directing pulses of light onto the surface of thematerial comprises using a laser for directing pulses of light onto thesurface of the material and wherein said pulses of light are directedonto the surface of the material in an overlapping arrangement.
 13. Themethod of processing a material, wherein the material has a surface, ofclaim 1 wherein said step of directing pulses of light onto the surfaceof the material comprises using a laser for directing multiple pulses oflight onto the surface of the material such that the multiple pulsesoverlap.
 14. The method of processing a material, wherein the materialhas a surface, of claim 1 further comprising using a second laser fordirecting multiple second pulses of light onto the surface of thematerial.
 15. The method of processing a material, wherein the materialhas a surface, of claim 1 further comprising using a second laser fordirecting second multiple pulses of light onto the surface of thematerial and wherein said second multiple pulses of light are onto thesurface of the material so that they overlap said multiple pulses oflight that are directed onto the surface of the material.
 16. A methodof processing a material, wherein the material has a surface and whereincontaminants are associated with the material; comprising the steps of:covering the material with a liquid providing an interface between thesurface of the material and said liquid, directing pulses of light ontothe surface of the material such that the interaction of said lightpulses with the surface of the material generates local pressure andtemperature producing a transient hydrothermal layer at the interfacebetween said liquid and the surface of the material, wherein saidtransient hydrothermal layer at least partially dissolves the materialproducing particles that are suspended in said liquid and at leastpartially dissolves or removes the contaminants.
 17. The method ofprocessing a material, wherein the material has a surface and whereincontaminants are associated with the material, of claim 16 whereinberyllium contaminants are associated with the material and wherein saidstep of directing pulses of light onto the surface of the materialcomprises directing pulses of light onto the surface of the materialsuch that the interaction of said light pulses with the surface of thematerial generates local pressure and temperature producing a transienthydrothermal layer at the interface between said liquid and the surfaceof the material, wherein said transient hydrothermal layer at leastpartially dissolves the material producing particles that are suspendedin said liquid and at least partially dissolves or removes the berylliumcontaminants.
 18. The method of processing a material, wherein thematerial has a surface and wherein contaminants are associated with thematerial, of claim 16 wherein radioactive contaminants are associatedwith the material and wherein said step of directing pulses of lightonto the surface of the material comprises directing pulses of lightonto the surface of the material such that the interaction of said lightpulses with the surface of the material generates local pressure andtemperature producing a transient hydrothermal layer at the interfacebetween said liquid and the surface of the material, wherein saidtransient hydrothermal layer at least partially dissolves the materialproducing particles that are suspended in said liquid and at leastpartially dissolves or removes the radioactive contaminants.
 19. Themethod of processing a material, wherein the material has a surface andwherein contaminants are associated with the material, of claim 16wherein rare earths contaminants are associated with the material andwherein said step of directing pulses of light onto the surface of thematerial comprises directing pulses of light onto the surface of thematerial such that the interaction of said light pulses with the surfaceof the material generates local pressure and temperature producing atransient hydrothermal layer at the interface between said liquid andthe surface of the material, wherein said transient hydrothermal layerat least partially dissolves the material producing particles that aresuspended in said liquid and at least partially dissolves or removes therare earths contaminants.
 20. The method of processing a material,wherein the material has a surface and wherein contaminants areassociated with the material, of claim 16 wherein lead contaminants areassociated with the material and wherein said step of directing pulsesof light onto the surface of the material comprises directing pulses oflight onto the surface of the material such that the interaction of saidlight pulses with the surface of the material generates local pressureand temperature producing a transient hydrothermal layer at theinterface between said liquid and the surface of the material, whereinsaid transient hydrothermal layer at least partially dissolves orremoves the contaminants the material producing particles that aresuspended in said liquid and at least partially dissolves or removes thelead contaminants.
 21. The method of processing a material, wherein thematerial has a surface and wherein contaminants are associated with thematerial, of claim 16 wherein lead paint contaminants are associatedwith the material and wherein said step of directing pulses of lightonto the surface of the material comprises directing pulses of lightonto the surface of the material such that the interaction of said lightpulses with the surface of the material generates local pressure andtemperature producing a transient hydrothermal layer at the interfacebetween said liquid and the surface of the material, wherein saidtransient hydrothermal layer at least partially dissolves the materialproducing particles that are suspended in said liquid and at leastpartially dissolves or removes the lead paint contaminants.
 22. Anapparatus for processing a material, wherein the material has a surface;comprising: means for covering the material with a liquid providing aninterface between the surface of the material and said liquid, means fordirecting pulses of light onto the surface of the material such that theinteraction of said light pulses with the surface of the materialgenerates local pressure and temperature producing a transienthydrothermal layer at the interface between said liquid and the surfaceof the material, wherein said transient hydrothermal layer at leastpartially dissolves the material.
 23. The apparatus for processing amaterial, wherein the material has a surface, of claim 22 wherein saidmeans for directing pulses of light onto the surface of the materialcomprises laser means for directing pulses of light onto the surface ofthe material.
 24. The apparatus for processing a material, wherein thematerial has a surface, of claim 22 wherein said means for directingpulses of light onto the surface of the material comprises laser meanswith visible or ultraviolet wavelengths for directing pulses of lightonto the surface of the material.
 25. The apparatus for processing amaterial, wherein the material has a surface, of claim 22 wherein saidmeans for directing pulses of light onto the surface of the materialcomprises an array of lasers means with visible or ultravioletwavelengths for directing pulses of light onto the surface of thematerial.